These studies are designed to evaluate the clinical benefits achieved by iron chelation in patients with chronic iron overload. Desferoxamine is administered by subcutaneous infusion and iron removal is determined by measurement of the serum ferritin and periodic non-invasive measurement of liver-iron concentration. Clinical status is evaluated by standard parameters including non-invasive testing of cardiac and endocrine function as indicated by the patient's age and risk category. The study is designed to document the natural history of severe beta thalassemia, treated effectively with regular transfusions and chelation therapy tailored to the patient's clinical status. The patients studied are both male and female, range in age from 5 to 70 years, and are Caucasian, African American, Oriental or Hispanic. We have established that regular daily subcutaneous infusion of Desferal reduces total body iron burden, prevents endocrine and cardiac complications, and reduces mortality in regularly tranfused patients with homozygous beta thalassemia (Cooley's Anemia). Similar studies in adult patients with acquired bone marrow disorders requiring regular transfusions have also suggested a clinical benefit of Desferal treatment. Our current studies are focused on evaluating these patients in detail to determine the occurrence and rate of complications related to iron overload. These clinical studies employ a drug approved for the treatment of iron overload that are focused on determining it's efficacy.